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https://issues.apache.org/jira/browse/KAFKA-7971?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16777528#comment-16777528
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Guozhang Wang commented on KAFKA-7971:
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I see: you have some logic which is not really data-driven but system-time
driven.
If you are using Processor API to construct your Topology already you can
consider using punctuation functions within a transformer, which is the parent
of a sink node sending to the topic, in the punctuator then, you can access the
store, and sends the result to the downstream sink node via
`ProcessorContext#forward()`, and in which case the sink node will be
responsible for sending the data to the topic.
Does that sounds right to you?
> Producer in Streams environment
> -------------------------------
>
> Key: KAFKA-7971
> URL: https://issues.apache.org/jira/browse/KAFKA-7971
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Maciej Lizewski
> Priority: Minor
> Labels: newbie
>
> Would be nice to have Producers that can emit messages to topic just like any
> producer but also have access to local stores from streams environment in
> Spring.
> consider case: I have event sourced ordering process like this:
> [EVENTS QUEUE] -> [MERGING PROCESS] -> [ORDERS CHANGELOG/KTABLE]
> Merging process uses local storage "opened orders" to easily apply new
> changes.
> Now I want to implement process of closing abandoned orders (orders that were
> started, but for too long there was no change and they hang in beginning
> status). Easiest way is to periodically scan "opened orders" store and
> produce "abandon event" for every order that meets criteria. The obnly way
> now i to create Transformer with punctuator and connect output to [EVENTS
> QUEUE]. That is obvious. but Transformer must be also connected to some input
> stream, but these events must be dropped as we want only the punctuator
> results. This causes unnecessary overhead in processing input messages
> (although they are just dropped) and it is not very elegant.
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